1. Field of the Disclosure
The disclosure relates to orthopedic devices used to reinforce bones in mammals and to a method of treating a humerus fracture. It specifically relates to cannulated bone screws and a method for using them.
2. Description of Relevant Art
Bone screws are used to reinforce bones by connecting at least two sections of a bone and/or by holding bone plates or other parts to a bone. It is often desirable to deliver medication and/or reinforcing material into the bone. A reinforcing material may be any kind of bone cement or bone graft or any other similar material. Specifically, delivery of bone cement into a bone material in close proximity of a bone screw may increase the mechanical retention of the bone screw within the bone material.
Cannulated bone screws are known from U.S. Pat. No. 6,048,343. The screw has a bore forming a central channel connected to sideward channels for delivering of bone cement into the bone surrounding the screw. A sealed adaptor is provided for connecting the screw to a dispensing device.
A further bone screw having a central channel is disclosed in U.S. Pat. No. 7,608,097 B2. A sleeve including a closed distal end can be inserted into the screw for selectively delivering a fluid to individual side holes connected to the central channel.
A further bone screw is disclosed in EP 1 210 019 B2. The screw has an inner bore connected to at least one sideward channel. The bore has a closed end so that no bone cement can penetrate through the tip of the screw.
A bone screw with a through hole and sideward openings for delivering a growth promoting agent is disclosed in US 2008/0269893. The screw is not intended to be removed from the bone. After the bone has grown into the structure of the screw, removal is impossible.
U.S. Pat. No. 8,197,517 discloses a bone screw with a blind hole and sideward openings. If cement has been introduced into the screw, removal is no longer possible.
In WO 2011/054122, a further bone screw having a blind hole and sideward openings is disclosed. The hole has inner structures or a slider to reduce the cross section and to improve distribution of material. Once cement has been introduced into the screw, removal is no longer possible.